Biology - Chapter 9 and 10 Flashcards
What is genetic diversity and how is it measured? How does a larger gene pool affect a population?
Refers to amount of genetic variation that exists between individuals. Is measured by reference go the populations gene pool which is the sum of all off the different genes and alleles present in a population and species. The larger of more diverse a populations gene pool, the greater the populations resilience to environmental change.
Types of sexual reproductive strategies
- Location of embryonic development
- Number of offspring produced per reproductive cycle
- The amount of prenatal care invested in each offspring.
What is oviparity?
When eggs are released to the external environment. The organism grows with little development inside the mother.
What is viviparity?
When the embryo develops inside the mothers body and is born after a period of gestation. Fertilisation occurs inside the mother.
What are advantages of sexual reproduction?
- Increases genetic diversity of a population by allowing for recombinant offspring
- Improves disease resistance by promoting the presence of different alleles
- combing the genetic material from 2 gametes reduces chances of an offspring inheriting a genetic disorder that might be carried by 1 parent
What are the disadvantages of sexual reproduction?
- the cost of male progeny
- the time, energy and resources it takes to attract and find a mate
- the risk of transferable disease associated with sexual intercourse
- the risk of losing offspring to outside influences such as embryo damage
How does pollination occur?
Angiosperms reproduce through pollination which is when pollen is collected by the stigma of the flower and fuses with the ovule. Then the embryo that develops with become a seed which contains nutrients to for an immature plant to bean to grow into a new plant under the right conditions.
What are the two categories pollinators can be?
Biotic - organisms that are attracted to brightly coloured petals, inviting smell and nutrient rich nectar
Abiotic - non living methods such as wind or water, allowing plants yo focus on maximising pollen dispersion then attracting pollinators.
Types of asexual reproduction
- binary fission
- budding
- fragmentation
- vegetative propagation
- sporogenesis
- parthenogenesis
What is binary fission?
A type of asexual reproduction where one organism divides into two identical organisms
What is budding?
A type of asexual reproduction where a group of cells form a bud and break away from the original organism to form a clone
What is fragmentation?
A type of asexual reproduction where a parent organism breaks into fragments each of which may develop into individual clones
What is vegetative propagation?
A type of asexual reproduction where a plant grows from fragments such as stem or toot cuttings of its parents
What is sporogenesis?
A type of asexual reproduction where spores form on the surface of the organism and are dispersed into the surroundings where they may develop into individual clones of the original
What is parthenogenesis?
A type of asexual reproduction where an embryo can develop from a single unfertilised gamete
Advantages of asexual reproduction
- asexually reproducing populations grow faster
- offspring are identical clones of parent - good for phenotype that is fine tuned to survive in that particular environment
- does not require an organs to find a mate (doesn’t need to be mobile)
- required little parental investment (removes need to protect offspring)
Disadvantages of asexual reproduction
- genetic diversity is low - therefore may suffer during rapid environmental change
What are the 2 types of reproductive cloning technologies in animals?
Somatic cell nuclear transfer and embryo splitting
Describe the stages of SNCT
It involves two different cells: a donated egg cell and a donated somatic cell from another animal
Stages are:
1. Enucleation – the removal or destruction of the nucleus from the donated egg cell to produce an enucleated egg cell.
2. Extraction – the donated somatic cell’s nucleus is extracted.
3.Insertion – the somatic cell’s nucleus is inserted into the enucleated egg cell.
4.Development – following insertion, the cell begins to divide and develop into an embryo, which is then implanted into a surrogate mother. The pregnancy then continues as normal.
In this process, the offspring produced is genetically identical to the donated somatic cell as they both contain the same nucleus and genetic material.
Complications of SNCT
- Animal suffering
- Human cloning (mass destruction of egg cells and embryos from failed attempts)
- Premature ageing
Explain embryo splitting
The division of an early embryo unto several individual embryos.
Stages:
1. Fertilisation
2. Early embryo (morula and is totipotent)
3. They are implanted into surrogate mothers
4. This produces genetically identical offspring
Complications of embryo splitting
- alteration of embryos
- decreased genetic diversity
- they become research animals
What are the reproductive cloning technologies in plants?
- Plant tissue culturing
- cutting
- grafting
What is plant tissue culturing/micropropagation
The cloning of plant cells on a nutrient culture medium in a controlled environment. A callus then forms which can be separated into several cultures and stimulated to grow into clones of the original plant
What are plant cuttings
The growth of plants using a fragment of the original
What is plant grafting
The attachment of two individual plant stems together (one is the scion and this is connected to a developed root system called the rootstock)
Advantages and disadvantages to plant cloning
advantages: provide plants with cold tolerance, resistance to disease and increased productivity
disadvantage: reduction in genetic diversity - more susceptible to disease, pests, and environmental change
Abiotic factors examples
- temperature
- humidity
- rainfall/water availability
- sunlight